Though several readers may need to obtain information from the same document, it is not always necessary for every reader to read all information printed on a document. As an example, many retail businesses send mass mailings to customers. These mass mailings can contain advertising and offer information that needs to be readily read. When customers return mailings with acceptances or in part, rejections of offers, the returned mailings need to be sorted before responses can be made to acceptances and partial rejections. For example, sortings can be made according to: (i) geographic location of addressee, e.g., by zip code; and (ii) whether there is acceptance or partial rejection of offers. Because of the large volume of mail that can be involved, such sorting needs to be automated. Pragmatically, this necessity for automation should be effected, if at all possible, without imposing an impersonal appearance to mailings that could unfavorably prejudice readers. As an example, impersonal appearance unavoidably arises when printed material includes bar codes and other printings not intended for the addressee. Achieving this goal of not including visible printed material required by the sender but not the addressee and also the goal of keeping simple procedures for responding to mailings are not always possible if return mail handling is to be automated.
A capability to read documents inside sealed envelopes would further expedite mail processing. Such expedition has heretofore been attempted by the use of differently colored or marked envelopes to be selected by addressees to indicate their response. This procedure violates both the goal for making mailing appear personal, i.e., returned mail will be personally handled, and also the goal of keeping mailings simple so addressees can understand and respond in a minimum amount of time with a minimum amount of effort.
The guarding of document security occasions additional problems. In particular, if more than an honor system is to be used, the task of assuring document security has heretofore required that all documents taken from secured areas must be quickly and accurately processed at check points, such as building or facility exits, to detect documents taken without authorization. Multipaged documents and also documents in envelopes or attache cases must be inspected quickly and hence without opening envelopes or attache cases.
Previously, to facilitate such inspections, every page containing sensitive information was either stamped or printed with a heading in bold bright lettering identifying the page as containing sensitive information to be kept secret and not disclosed. If a page with such a heading is in plain sight, there is no difficulty in identifying it as not being available for public disclosure. On the other hand, such headings are of very limited to no use when the marked pages are included with unmarked pages in thick documents, or the marked pages are in sealed envelopes or closed attache cases.
An associated situation to using a marked heading on documents containing confidential information arises when markings such as watermarks are used on valuable documents not to be counterfeited or copied in any fashion for use as an original. Again, the same disability to read marks when documents are covered and not visible arises. Further, accurate and fast readings of watermarks and the like which are not readily visible even when a document is in plain view are frustrated.